U.S. Pat. Nos. 4,641,140 and 4,695,810 to D. Heckaman et al, assigned to the assignee of the present application and the disclosures of which are incorporated herein, describe various embodiments of compact RF signalling structures, known as `channelline` and `waffleline` configurations, in which a dielectric-clad conductor is placed in a conductive-walled channel, which forms the ground plane for the transmission line. Advantageously, such channelline and waffleline-configured transmission line architectures provide a physically `thin` interconnect structure, that enables the overall physical size of both the interconnect structure and the attendant communication circuit components it interconnects to be housed in a very compact configuration, including conformal shapes for use on airborne and spaceborne-mounted platforms.
In the case of channelline, the transmission channel may follow an arbitrary path through the support structure, whereas waffleline has a matrix or grid-like structure of mesas and surrounding channels, taking on a waffle iron-like shape and having a prescribed characteristic impedance irrespective of the path followed by the conductor through the waffleline.
Because the communication circuit components with which such RF interconnect structures are employed require non-RF signalling links such as power and control (usually digital) signalling, it is necessary to provide separate signalling highways for that purpose. One technique that has been used in the case of a waffleline interconnect structure has been to route the auxiliary signalling wires through channels of the waffleline (other than those used for RF signalling). Because these auxiliary signalling wires are dimensioned smaller than the RF wires, they have been customarily installed by hand, usually with multiple wires being placed together in the same channels, so as to cause a bundling of the wires as they are routed through among the mesas of the waffleline. An additional mechanism has involved the use of a separate printed circuit board across which the auxiliary signalling wires are routed, the separate printed circuit board being attached (typically by way of stand-offs and bolts) to the channelline or waffleline structure, so that it involves both the installation of a separate routing fixture and the need to wire that fixture by hand.